Teaching differs from simply broadcasting information in that the teacher must modify their behaviour, at some cost, to assist a naïve observer(my edit-me) to learn more quickly.
This is what Franks and Richardson found - follower ants would indeed find food faster when tandem running than when simply searching for it alone, but at the cost to the teacher (my edit-TOD) who would normally reach the food about four times faster if foraging alone.

Journal reference: Nature (DOI: 10.1038/439153a)

 Output fell to 4.01 million barrels of oil equivalent a day, 2.2 percent less than the 4.1 million reported in the year-earlier period, London-based BP said today in a statement. BP said it would cut more than 1,000 jobs in Europe to reduce costs.

The Texas City plant, the third-biggest refinery in the U.S., remains closed after a March explosion and damage from the storms and is a setback for BP at a time of high oil prices.

BP said fourth-quarter costs would include $130 million, partly to repair Thunder Horse (my edit-at least $110 m partly and TH doesn't get into the GOM until 07).

So BP's Texas City down, 3 refineries East of NO down along with Pascagoula and the heavy crude Valero plants can't process without hydrogen-the Airgas plant producing the Hydrogen destroyed outside NO.

That's 6 refineries down, still, or producing at much less than capacity.